Liquid crystal display device and analysis device including the same

ABSTRACT

In order to provide a liquid crystal display device which can detect a defective indication due to short circuit which occurs between a common electrode and a counter electrode by a conductive impurity enters into a liquid crystal display panel, and an analysis device including the same, a blood glucose meter includes a display section and a microcomputer. For performing an inspection for a defective indication on a liquid crystal display panel of the display section, the microcomputer uses ports as input/output ports for a defective indication inspection. The microcomputer detects whether an inspection signal sent from the port can be received at the other port or not to perform the inspection for a defective indication.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 11/629,175 filed Dec. 11, 2006, which is a nationalphase filing of PCT/JP05/011922 filed Jun. 29, 2005. U.S. patentapplication Ser. No. 11/629,175 claims priority under 35 U.S.C. §119(a)to Japanese Patent Application No. 2004-199728 filed Jul. 6, 2004. Theentire disclosures of U.S. patent application Ser. No. 11/629,175,PCT/JP05/011922, and Japanese Patent Application No. 2004-199728 arehereby incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a liquid crystal display device of asegment method, dot matrix method, or the like, which displays numeralsand texts, and an analysis device including the same.

BACKGROUND OF THE INVENTION

Recently, liquid crystal display devices are incorporated into a varietyof electronic equipment, such as clocks, calculators, analysis devices,home electric appliances and the like as display sections.

For example, one type of a liquid crystal display device which displayssimple indication such as numerals and texts is a liquid crystal displaydevice of a segment method. The liquid crystal display device of thesegment method includes a common electrode which is formed on one of twosubstrates, a plurality of segmented electrodes which are patterned intothe shape of numerals on the other substrate, and a liquid crystalenclosed between the two substrates. A voltage is applied between thecommon electrode and the segmented electrodes, and an orientation of theliquid crystal enclosed therebetween is changed to control transmissionof light. In this way, texts and numerals can be displayed.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, the above conventional liquid crystal display device has thefollowing problems.

In the liquid crystal display device of the segment method as disclosedin Japanese Laid-Open Publication No. 7-128338, if a conductive impurityenters between the above-described common electrode and the segmentedelectrodes, a short circuit occurs between the common electrode and thesegmented electrodes. A difference in potential is lost, and anappropriate indication cannot be displayed (see FIGS. 5A and 5B). Eventhough such a defective indication is not observed when the product ismanufactured, it may suddenly appear while in use for some reason. Thus,an inspection of a defective indication at the shipping of products ishardly sufficient as the measures to address such a problem.

Moreover, if such a defective indication appears in a liquid crystaldisplay device incorporated in a blood glucose meter which is used by adiabetic patient for measuring a blood glucose level by oneself, thediabetic patient or the like may not notice that the wrong indication isdisplayed. Blood glucose level control by an injection of insulin or thelike conducted in accordance with the erroneously displayed bloodglucose level is not an appropriate treatment for the patient whomeasures the blood glucose level. Particularly, many of the people whotake blood, such as diabetic patients, are elderly or visuallyhandicapped people. Thus, it can be expected that they do not notice thedefective indication of the liquid crystal display device. However, theconventional liquid crystal display devices incorporated in the bloodglucose meters do not include means for detecting defective indication,or means for notifying the defective indication in particular.

An object of the present invention is to provide a liquid crystaldisplay device which can detect a defective indication which appears dueto a short circuit between a common electrode and a counter electrodethereof caused by a conductive impurity entering into a liquid crystaldisplay panel, and an analysis device including the same.

Means for Solving the Problems

A liquid crystal display device according to claim 1 includes a liquidcrystal display panel, an input and output section, and a controlsection. The liquid crystal display panel includes a first substratewith a first electrode formed thereon, a second substrate with a commonelectrode formed thereon and a liquid crystal enclosed between the firstsubstrate and the second substrate. The liquid crystal display paneldisplays by changing an orientation of the liquid crystal by adifference in potential applied between the first electrode and thecommon electrode. The input and output section has a first outputterminal and a second output terminal configured to drive the liquidcrystal display panel. The first output terminal sends a signal to thefirst electrode. The second output terminal sends a signal to the commonelectrode.

The control section uses the first output terminal and the second outputterminal of the input and output section as input and output terminalsfor a defective indication inspection configured to perform aninspection for a defective indication in the liquid crystal displaypanel. The control section performs the inspection for a defectiveindication by detecting whether a signal sent from one of the input andoutput terminals of the input and output section can be received at theother of the input and output terminals.

With such a structure, the first output terminal and the second outputterminal which are respectively connected to the first electrode sideand the common electrode side opposing the first electrode and which areused as output terminals for driving the liquid crystal when a normalindication is displayed are used as the input and output terminals forthe defective indication inspection to perform an inspection for adefective indication in the liquid crystal display panel. During thedefective indication inspection, if the signal sent from the one inputand output terminal is received at the other input and output terminal,the control section detects an presence of a defective indication.

In such a structure, when a conductive impurity enters between thecommon electrode and the opposing first electrode, a short circuitoccurs between the common electrode and the first electrode and adifference in potentials is lost. Thus, an appropriate indication cannotbe displayed.

Thus, for detecting such the presence of a defective indication, theliquid crystal display device of the present invention uses the outputterminal on the first electrode side and the output terminal on thecommon electrode side which are used as output terminals for driving theliquid crystal when a normal indication is displayed are used as theinput and output terminals for the defective indication inspection.Then, whether the signal sent from one input and output terminal can bereceived at the other input and output terminal or not is checked. Ifthe signal can be received at the other input and output terminal, itmeans that there is a conductive impurity which connects the firstelectrode and the common electrode in the liquid crystal.

In this way, by only using the output terminals (on the first electrodeside and the common electrode side) for driving the liquid crystal areused as the input and output terminal for the inspection to detect thatthe signal sent from one input and output terminal is received at theother input and output terminal, the defective indication due to a shortcircuit caused in the liquid crystal display device can be readilydetected.

The first electrode mentioned above corresponds to a segmented electrodein a liquid crystal display device of a segment method, and to a counterelectrode formed on a first substrate at a position which corresponds todots in a liquid crystal display device of a dot matrix method.

A liquid crystal display device according to claim 2 is a liquid crystaldisplay device according to claim 1 in which the control sectiondisplays a message notifying that a defective indication appears on theliquid crystal display panel when the control section detects thedefective indication.

With such a structure, when an appearance of a defective indication isdetected, for example, a text saying that defective indication isappearing is displayed on the liquid crystal display panel, lamp is lit,a displayed numerals are flickered, or the like.

In this way, it becomes possible to surely notify the user that thecurrent indication is not correctly displayed. Thus, a diabetic patientcan be prevented from conducting blood glucose control in reliance onthe erroneously displayed blood glucose measured value.

A liquid crystal display device according to claim 3 is a liquid crystaldisplay device according to claim 1 in which the control section soundsan alarm sound when it detects the defective indication.

With such a structure, an alarm sound is sounded when the presence of adefective indication is detected. In this way, it becomes possible tosurely notify the user that the current indication is not correctlydisplayed.

Accordingly, a diabetic patient or a visually handicapped person can beprevented from conducting blood glucose control in reliance on theerroneously displayed blood glucose measured value.

A liquid crystal display device according to claim 4 is a liquid crystaldisplay device according to claim 1 in which the control section stopsdisplaying on the liquid crystal display panel when it detects thedefective indication.

With such a structure, when the control section detects a defectiveindication, the device is controlled to stop displaying the numericalvalues or the like on the liquid crystal display panel.

In this way, visually handicapped patients such as elderly people can besecurely prevented from conducting blood glucose control in reliance onthe erroneously displayed blood glucose measured value. Thus, a liquidcrystal display device with higher safety can be provided.

A liquid crystal display device according to claim 5 is a liquid crystaldisplay device according to any one of claim 1 in which the controlsection performs the inspection for a defective indication every timepower is turned on, and/or the display is switched.

With such a structure, the inspection for the defective indication isperformed every time when the power is turned on before displaying orthe display is switched.

In this way, in the liquid crystal display section incorporated in theblood glucose meter, the inspection for a defective indication isperformed every time when the power is turned on before displaying orthe display is switched. When a defective indication appears, measuressuch as notifying by an alarm sound is taken. Thus, it becomes possibleto prevent the user from believing in the displayed numeral to becorrect in the case of appearance of the defective indication.

An analysis device according to claim 6 includes a liquid crystaldisplay device according to any one of claim 1 as a display section.

With such a structure, the liquid crystal display device of the presentinvention can be used as, for example, a display section of an analysisdevice such as blood glucose meter.

In this way, the presence of a defective indication caused by aconductive impurity enters into a liquid crystal layer can be detectedand notified to the user. Thus, it becomes possible to prevent the userfrom believing in the displayed numeral to be correct in the case ofappearance of the defective indication and conducting wrong treatmentsuch as performing inappropriate blood glucose control or the like.

FUNCTION OF THE INVENTION

According to the liquid crystal display device of claim 1, the presenceof a defective indication caused by a conductive impurity enters into aliquid crystal layer can be detected.

According to the liquid crystal display device of claim 2, it becomespossible to surely notify the user that the current display is notcorrect.

According to the liquid crystal display device of claim 3, a user can beprevented from performing blood glucose level control in reliance of anerroneously displayed blood glucose measure value.

According to the liquid crystal display device of claim 4, a visuallyhandicapped patient such as an elderly person can be securely preventedfrom performing blood glucose level control in reliance of anerroneously displayed blood glucose measure value.

According to the liquid crystal display device of claim 5, when adefective indication appears, measures such as notifying by an alarmsound can be taken.

According to the analysis device of claim 6, the presence of a defectiveindication caused by a conductive impurity enters into a liquid crystallayer can be detected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing a blood glucose meter as an example of ananalysis device which includes a liquid crystal display device of thepresent invention as a display section.

FIG. 2A is a diagram showing a normal indication state of the bloodglucose meter of FIG. 1; and FIG. 2B is a diagram showing an inspectionstate for a defective indication.

FIGS. 3A and 3B are diagrams showing how an inspection signal is sentand received when there is no defective indication.

FIGS. 4A and 4B are diagrams showing how an inspection signal is sentand received when a defective indication appears.

FIGS. 5A and 5B are diagrams showing a display section with a defectiveindication.

FIG. 6 is a block diagram showing a connection state with amicrocomputer incorporated in the blood glucose meter of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

A blood glucose meter (analysis device) 10 including a display section(liquid crystal display device) 11 according to an embodiment of thepresent invention is described as follows with reference to FIGS. 1through 6.

Structure of Entire Blood Glucose Meter

As shown in FIG. 1, the blood glucose meter 10 according to the presentembodiment is a blood glucose measurement device which includes thedisplay section (liquid crystal display device) 11, and a sensor section12, and also incorporates a microcomputer (control section) 15 (see FIG.2) inside.

The display section 11 is a liquid crystal display device of a segmentmethod which displays a blood glucose level measured by depositing bloodon the sensor section 12. As shown in FIG. 1, the display section 11displays a numerical value to two places to the left to the decimalpoint and one place to the right of the decimal point (result ofmeasurement of the blood glucose level). The display section 11 alsodisplays a remaining battery life of the blood glucose meter 10, and thelike. A normal indication of the display section 11, an inspection of adefective indication, and the like will be described later in details.

The sensor section 12 includes a sensor 12 a for depositing a bloodflowed from a puncture wound formed by a lancet or the like formeasuring the blood glucose level at a predetermined position of its tipportion. The blood deposited on the sensor 12 a is analyzed, and theblood glucose level is measured.

The microcomputer 15 is a microcomputer of an internal LCD driver typewhich drives a liquid crystal of the display section 11. As shown inFIG. 2A, the microcomputer 15 includes ports (input and output sectionwhich are the first and second output terminals) 15 a and 15 b which areconnected to an SEG (segmented electrode which is the first electrode)and a COM (common electrode) of the display section 11. Themicrocomputer 15 uses the ports 15 a and 15 b as ports of the LCD driverfor driving the liquid crystal of the display section 11 during normalindication. How the ports 15 a and 15 b are handled by the microcomputer15 in the inspection for a defective indication will be described laterin details.

Structure of Display Section

As shown in FIG. 1, the display section 11 includes a liquid crystaldisplay panel 11 a. Furthermore, as shown in FIGS. 2A and 2B, thedisplay section 11 includes the SEG formed on one of the substrateswhich form the liquid crystal display panel 11 a of the display section11, and the COM formed on the other substrate. By applying a voltagebetween the SEG and the COM, an alignment of the liquid crystal enclosedbetween the two substrates is changed. Thus, segmented portions arerespectively switched between a displaying state and a non-displayingstate.

The SEG is a segmented electrode patterned on one substrate as sevensegments for displaying numerals. The COM is an electrode formed acrossa surface of the other substrate. The SEG and the COM are connected tothe ports 15 a and 15 b of the microcomputer 15 which functions as theports of the LCD driver. The SEG and the COM receive a signal (voltage)sent from the microcomputer 15 in accordance with the result ofmeasuring the blood glucose level. Thus, a difference in potentials isgenerated between the SEG and the COM, and the alignment of the liquidcrystal between the SEG and the COM required for displaying a desirednumeral is changed to display the blood glucose level.

Now, a case of a defective indication caused by an impurity trapped inthe liquid crystal display panel 11 a of the display section 11 isdescribed.

As described above, a numeral is displayed on the display section 11 bygenerating a difference in potentials between the SEG and the COM.However, when a conductive impurity enters between the SEG and the COM,the potential difference between the SEG and the COM is lost. Thus, inthe segmented portions where the alignment of the liquid crystal shouldbe changed for display, the alignment of the liquid crystal remainsunchanged, causing the portions not to be displayed. This results in adefective indication (see FIGS. 5A and 5B).

When such a defective indication appears in a liquid crystal displaydevice used as the display section 11 of the blood glucose meter 10 asin the present embodiment, a user may misunderstand that the numeralserroneously displayed is a correct measurement result, and injectinsulin for blood glucose control based on the wrong measured value.Such a wrong blood glucose control is just an inappropriate treatmentfor a diabetic patient. Rather, it may be harmful for the patient.Particularly, many of the diabetic patients who use the blood glucosemeter 10 as in the present embodiment have weak eyesight. They mayfalsely recognize the defective indication as shown in FIG. 5A to be“60.0”, for example, without noticing that it is a defective indication.

Thus, in the blood glucose meter 10 of the present embodiment, in orderto prevent an inappropriate treatment caused by misunderstanding of theuser, a defective indication is checked for every time the blood glucosemeter 10 is powered on and/or the display is switched, and, when theappearance of a defective indication is detected, the user is notifiedof the appearance of the defective indication.

Structure of Microcomputer

As shown in FIGS. 2A and 2B, the microcomputer 15 includes the port 15 aconnected to the SEG side of the display section 11 and the port 15 bconnected to the COM side. Furthermore, as shown in FIG. 6, themicrocomputer 15 is connected to the display section 11, the sensorsection 12, an alarm section 16, and a power supply section 17.

For a normal indication, in the microcomputer 15, a signal (voltage) issent from the port 15 a to the SEG corresponding to the segments to bedisplayed based on the blood glucose level measured at the sensorsection 12. To the COM side, a signal (voltage) is sent from the port 15b at a timing of displaying.

The microcomputer 15 also performs various types of controllingoperations such as checking for a defective indication which appearswhen a conductive impurity enters into the liquid crystal display panel11 a, analyzing the blood detected at the sensor section 12 andcalculating the blood glucose level, and the like, in addition to drivecontrol of the liquid crystal display panel 11 a of the display section11.

As shown in FIG. 2B, specifically, the inspection for a defectiveindication is performed using the ports 15 a and 15 b used as outputterminals of the LCD driver as I/O ports (input and output terminals)for the defective indication inspection.

The alarm section 16 sounds a buzzer to notify the user that thecurrently displayed numerical value is a wrong indication when themicrocomputer 15 detects a defective indication in the inspection forthe defective indication.

The power supply section 17 which supplies power to electronic equipmentincorporated in the blood glucose meter 10 stops the power supply to thedisplay section 11 when the microcomputer 15 detects a defectiveindication.

An Inspection Method of the Present Blood Glucose Meter

An inspection method for a defective indication in the blood glucosemeter 10 of the present embodiment is described as follows withreference to FIGS. 3A through 4B.

In the blood glucose meter 10 of the present embodiment, every time thepower is turned on, and/or the display is switched, the microcomputer 15uses the ports 15 a and 15 b as the I/O ports. As shown in FIG. 3A, aninspection signal is sent from one of the ports, the port 15 a, which isconnected to the SEG. Whether the inspection signal can be received ornot at the other port, the port 15 b which is connected to the COM, ischecked. In other words, whether there is a short circuit between theSEG and the COM of the liquid crystal display panel 11 a is checked.Such an inspection is performed between all the SEGs and the COMs.Alternatively, as shown in FIG. 3B, the inspection signal may be sentfrom the other port 15 b and whether the inspection signal can bereceived or not at the one port 15 a may be checked.

If there is an impurity trapped between the SEG and the COM of theliquid crystal display panel 11 a and there is short-circuit as shown inFIGS. 4A and 4B, the difference in potentials between the SEG and theCOM is lost, and the alignment of the liquid crystal cannot be changed.Thus, the segmented portions which should be displayed cannot bedisplayed, and a defective indication as shown in FIGS. 5A and 5B mayappear.

In the blood glucose meter 10 of the present embodiment, when appearanceof such a defective indication is detected, the inspection signal sentfrom the one port 15 a is detected at the other port 15 b as shown inFIG. 4A since there is a short circuit between the SEG and the COM ofthe liquid crystal display panel 11 a. The same is also true of the casewhere the inspection signal sent from the other port 15 b is detected atthe one port 15 a as shown in FIG. 4B.

When the inspection signal sent from the port 15 a or the port 15 b isreceived at the port 15 b or the port 15 a, the microcomputer 15controls the alarm section 16 to sound a buzzer. Further, themicrocomputer 15 has the liquid crystal display panel 11 a of thedisplay section 11 to display a message notifying that a defectiveindication is present.

In this way, it becomes possible to surely notify the user that adefective indication appears and the numeral displayed on the liquidcrystal display panel 11 a is wrong.

Features of the Present Blood Glucose Meter

(1)

The blood glucose meter 10 of the present embodiment includes thedisplay section 11, the microcomputer 15, and the like. The ports 15 aand 15 b used as the output terminals of the LCD driver when a normalindication is displayed are used as the I/O ports for the inspectionwhen the inspection for a defective indication is performed. In a use asthe I/O ports, for example, an inspection signal is sent from the oneport 15 a which is connected to the SEG of the liquid crystal displaypanel 11 a. If the inspection signal is received at the other port 15 bwhich is connected to the COM of the liquid crystal display panel 11 a,the microcomputer 15 detects the presence of a defective indication.

In this way, it is ensured that a defective indication due to a shortcircuit caused by an impurity trapped between the SEG and the COM of theliquid crystal display panel 11 a is detected. As a result, it becomespossible to prevent treatment such as wrong blood glucose control due toa defective indication appearing on the blood glucose meter 10 which isused by diabetic patients including a number of visually handicappedelderly people.

(2)

In the blood glucose meter 10 of the present embodiment, when theappearance of the defective indication as described above is detected,the microcomputer 15 has the display section 11 to display a messagenotifying of the “presence of a defective indication”.

In this way, it becomes possible to ensure notifying the user of theappearance of the defective indication. As a result, problems such asconducting inappropriate treatment in reliance on an erroneouslydisplayed numerical value can be avoided.

(3)

In the blood glucose meter 10 of the present embodiment, when theappearance of the defective indication as described above is detected,the microcomputer 15 controls the alarm section 16 to sound a buzzer.

In this way, it becomes possible to further ensure notifying the user ofthe existence of the defective indication. As a result, problems such asconducting inappropriate treatment in reliance on an erroneouslydisplayed numerical value can be avoided.

As in the present embodiment, a plurality of warning means, such asdisplaying a message notifying of a defective indication, an alarm by abuzzer and the like may be combined.

(4)

In the blood glucose meter 10 of the present embodiment, the inspectionfor a defective indication as described above is performed every timethe power of the blood glucose meter 10 is turned on, and/or the displayis switched.

In this way, basically, whether there is the presence of a defectiveindication or not can be checked every time the blood glucose level ismeasured. Thus, a blood glucose meter with higher safety can beprovided.

OTHER EMBODIMENTS

An embodiment of the present invention has been described above.However, the present invention is not limited to the above-describedembodiment, and various modifications can be applied without departingfrom the gist of the invention.

(A)

In the above embodiment, the liquid crystal display device of thepresent invention is described as a display section incorporated in ablood glucose meter. However, the present invention is not limited tosuch an example.

For example, when the present invention is applied as a display sectionof a variety of analysis devices other than the blood glucose meter,similar effects as described above can be achieved.

(B)

In the above embodiment, when the presence of a defective indication isdetected, the appearance of the defective indication is notified to theuser by a combination of displaying a message notifying of theappearance of the defective indication, and the buzzer by the alarmsection 16. However, the present invention is not limited to such anexample.

For example, among these two control operations, only one of them may beperformed. Alternatively, the power supply section 17 shown in FIG. 6may be controlled such that when the appearance of the defectiveindication is detected, the power supply to the display section 11 isstopped.

In such an example, it is also possible to avoid the user conducting theblood glucose control without noticing that the displayed numericalvalue is wrong due to the defective indication.

In view of a secure notification to visually handicapped users, it ismore preferable to combine a plurality of control operations as in theabove-described embodiment.

(C)

In the above-described embodiment, the LCD driver is incorporated withinthe microcomputer 15. However, the present invention is not limited tosuch an example.

For example, even when the LCD driver is provided separately from themicrocomputer 15, the similar effects as described above can be achievedby using the ports of the LCD driver as the I/O ports.

(D)

In the above-described embodiment, the present invention is applied tothe liquid crystal display device of the segment method (the firstelectrode corresponds to a segmented electrode). However, the presentinvention is not limited to such an example.

For example, the present invention can also be applied to a liquidcrystal display device of a dot matrix method with a relatively smallnumber of dots. In such an example, the first electrode corresponds to acounter electrode formed on a first substrate at a positioncorresponding to the dots.

INDUSTRIAL APPLICABILITY

The liquid crystal display device of the present invention has effectswhich enable detection of a defective indication due to an impurityenters into a liquid crystal display panel with a simple structure.Thus, it is applicable not only to liquid crystal display devices of thesegment method but also to a wide variety of liquid crystal displaydevices.

1. A liquid crystal display device, comprising: a liquid crystal displaypanel which includes a first substrate with a first electrode formedthereon, a second substrate with a common electrode formed thereon and aliquid crystal enclosed between the first substrate and the secondsubstrate, and which displays by changing an orientation of the liquidcrystal by a difference in potential applied between the first electrodeand the common electrode; an input and output section which has a firstoutput terminal which sends a signal to the first electrode and a secondoutput terminal which sends a signal to the common electrode configuredto drive the liquid crystal display panel; a control section which usesthe first output terminal and the second output terminal of the inputand output section as input and output terminals for a defectiveindication inspection configured to perform an inspection for adefective indication in the liquid crystal display panel, and whichperforms the inspection for a defective indication by detecting whethera signal sent from one of the input and output terminals of the inputand output section can be received at the other of the input and outputterminals and performs the inspection for a defective indication everytime power is turned on, and/or the display is switched, and stopssupply of electric power to the liquid crystal display panel in responseto detection of a defective indication.
 2. A liquid crystal displaydevice according to claim 1, wherein the control section displays amessage notifying that a defective indication appears on the liquidcrystal display panel when the control section detects the defectiveindication.
 3. A liquid crystal display device according to claim 1,wherein the control section sounds an alarm sound when it detects thedefective indication.
 4. A liquid crystal display device according toclaim 1, wherein the control section performs the inspection for adefective indication every time power is turned on, and/or the displayis switched.
 5. An analysis device comprising: a liquid crystal displaydevice according to claim 1 as a display section.